1. Field of the Invention
The present invention relates to an improved display section for a multilayer gas-discharge display panel and, more particularly, to a method and means for controlling the brightness and power dissipation and for providing selective erasure in a multilayer gas-discharge display panel.
2. Description of the Prior Art
The multilayer gas-discharge display panel is a new type of high brightness dot-matrix display with inherent storage capability. It contains a layered addressing system which reduces drive circuit requirements to low levels even for relatively high information content displays. It responds directly to digital signals from a computer and has a resolution comparable to that of cathode ray tube displays.
A known type of multilayer gas-discharge display panel contains a large number of character blocks, each including three basic sections, a plasma supply reservoir section, a control anode section, and a display section, each of such sections being interconnected by an array of parallel channels or columns, one for each resolution element in the display. Each column is filled with a gas which can be broken down to form a visible glow. A gas-discharge is ignited in the reservoir section at the back of the panel by applying a suitable voltage between the reservoir cathode and the reservoir anode to provide positive and negative ions for each column. The control anodes are a set of parallel, spaced, segmented electrodes which serve to extend one or more selected ion columns through to the display section. A voltage is applied between the display section cathode and anode to initiate a gas breakdown therein, such voltage being insufficient to initiate a breakdown except in those columns in which ions have been conducted to the display section. In such case, the field between the display section cathode and anode induced by the applied voltage adds to the field created by the ions to initiate a gas breakdown. The display section typically operates in a pulsed-memory mode with the breakdown and glow sustained after the reservoir and control anode voltages have been removed.
While such a multilayer gas-discharge display panel has several inherent advantages suggesting its widespread use, two fundimental problems have contributed to preventing its adoption. That is, for most application, the light output of existing multilayer gas-discharge display panels is too high. Because of the high output intensity, there is too much power drain by the display panel and this high power dissipation has been found to be objectionable.
Another problem with conventional multilayer gas-discharge display panels is that it is impossible to provide selective erasure. That is, with conventional display panels, the display is activated by writing each resolution element, one at a time, until the entire panel is activated. If it is desired to extinguish a resolution element, all resolution elements in a particular matrix must be extinguished and rewritten. Again, this is highly undesirable in a variety of circumstances.